I've had my two male parakeets, Sergio & Isabella for a little over three months now. The employee at the pet store incorrectly determined Isabella as a female, hence the name, but she is most definitely a male bird. I'd been calling her Isabella for so long, it's been hard for me to come up with anything else to name her.

But anyways, I bought them from the same place, at the same time, quarantined them separately, and then brought them together. Their 30 X 18 X 18 had two food dishes, two water fountains two swings, two cuttle bones, and plenty of toys to be shared. However, Sergio has been progressively & constantly mean to Isabella for the past 3 days. Today, Isabella nudged one of the toys at the left hand side of the cage while Sergio was residing at the opposite end of cage. Sergio saw her touch the toy & flew all the way over to peck Isabella off her the perch. And even with two food dishes, Sergio doesn't like her eating from either of them.

I finally separated them after watching Sergio bully her all day long. I understand Sergio is being overly territorial, but what else could I do to see that they get along, other than separating them?

Yeah, it differs. Cockatiels and their big brothers the cockatoos have a lot of agression between males. With budgies its the female thats agressive. Males have a 'disagreement', they beak a little bit and then its over. Usually they dont even beakfight at all, they just puff up and use their whole repertoire of matingbehavior. Walking back and forth shouting insultations. Deciding which one is the dominant one without fighting. When the peckingorder is set, they go back to being buddies. Females really fight and sometimes kill eachother.

OH MY GOODNESS! How awful! I split them up and it was so sad they were looking for each other! Still not sure if they're girls or not, but I'm going to take a picture & get a second opinion. Their ceres are light blue & white, so... I don't know. I thought that indicated that they were males...? They're definitely beakfighting though and aggressive enough to push the other off their perch during the day. What's odd is that they share a swing when they sleep & even nuzzle when the day is winding down...?

Bleu ceres with white edges around the nostrils are females. The colour can vary from light blue to beige. When they go into brood the ceres turn brown or black. Males have bright blue to dark purple ceres.

If they sleep together on a perch and groom eachother then theres no direct problem. Females can be friends together, and by the sound of it they are. But female budgies are bitchy. They will try to push eachother off perches and beak eachother. And when they go into brood you might get a problem when they get hormonal.